Aqueous leather treatment composition and method of use

Abstract

An aqueous leather treatment composition is provided containing select soft polymer particles and water-filled voided particles. Also provided are a method for preparing an embossed coated leather substrate, which includes the application of the aqueous leather treatment composition, as well as an article prepared from the embossed coated leather substrate.

1. An aqueous leather treatment composition comprising:
 a) polymer particles selected from:
 i) polyurethane polymer particles having a glass transition temperature of less than or equal to 20° C., 
 ii) addition polymer particles having a glass transition temperature in the range of from −70° C. to 10° C., or 
 iii) combinations thereof; and 
 
 b) water-filled voided particles having an average particle diameter in the range of from 0.1 to 4 micron; 
 wherein said aqueous leather treatment composition has a ratio of dry weight of said polymer particles to dry weight of said water-filled voided particles in the range of from 19:1 to 3:2. 
 
     
     
       2. The aqueous leather treatment composition according to  claim 1 , wherein said aqueous leather treatment composition comprises:
 a) said addition polymer particles, wherein said addition polymer particles comprise copolymerized carboxylic acid monomer; and 
 b) at least one transition metal oxide, hydroxide, or carbonate in an amount greater than 0.2 equivalent of transition metal per equivalent of said copolymerized carboxylic acid monomer. 
 
     
     
       3. The aqueous leather treatment composition according to  claim 1  wherein said addition polymer particles are multistage polymer particles comprising, based on dry weight of said multistage polymer particles:
 a) 80 to 90 weight % of a predominately (meth)acrylic first polymer with a glass transition temperature in the range of from −70° C. to zero ° C.; and 
 b) 10 to 20 weight % of a second polymer having a glass transition temperature of at least 20° C. 
 
     
     
       4. The aqueous leather treatment composition according to  claim 1  further comprising from 5 to 30 weight % of additional polymer particles having a glass transition temperature in the range of from 40° C. to 150° C., based on total weight of said polymer particles and said additional polymer particles. 
     
     
       5. A method for preparing an embossed coated leather substrate, comprising the steps of:
 a) applying an aqueous leather treatment composition to a leather substrate, wherein said aqueous leather treatment composition comprises:
 i) polymer particles selected from:
 A) polyurethane polymer particles having a glass transition temperature of less than or equal to 20° C., 
 B) addition polymer particles having a glass transition temperature in the range of from −70° C. to 10° C., or 
 C) combinations thereof; and 
 
 ii) water-filled voided particles having an average particle diameter in the range of from 0.1 micron to 4 micron; 
 
 
       wherein said aqueous leather treatment composition has a ratio of dry weight of said polymer particles to dry weight of said water-filled voided particles in the range of from 19:1 to 3:2;
 b) drying or allowing to dry said aqueous leather treatment composition that is applied to said leather substrate to provide a coated leather substrate having a coated surface; 
 c) contacting said coated surface of said coated leather substrate and an engraved surface; 
 d) applying pressure to interface of said coated surface in contact with said engraved surface; and 
 e) removing from contact said engraved surface and said coated surface to provide said embossed coated leather substrate. 
 
     
     
       6. The method according to  claim 5 , wherein said aqueous leather treatment composition comprises:
 a) said addition polymer particles, wherein said addition polymer particles comprise copolymerized carboxylic acid monomer; and 
 b) at least one transition metal oxide, hydroxide, or carbonate in an amount greater than 0.2 equivalent of transition metal per equivalent of said copolymerized carboxylic acid monomer. 
 
     
     
       7. The method according to  claim 5  wherein said addition polymer particles are multistage polymer particles comprising, based on dry weight of said multistage polymer particles:
 a) 80 to 90 weight % of a predominately (meth)acrylic first polymer with a glass transition temperature in the range of from −70° C. to zero ° C.; and 
 b) 10 to 20 weight % of a second polymer having a glass transition temperature of at least 20° C. 
 
     
     
       8. The method according to  claim 5 , wherein said aqueous leather treatment composition further comprises from 5 to 30 weight % of additional polymer particles having a glass transition temperature in the range of from 40° C. to 150° C., based on total weight of said polymer particles and said additional polymer particles. 
     
     
       9. The aqueous leather treatment composition according to  claim 1 , wherein said addition polymer particles have a glass transition temperature in the range of from −60° C. to 10° C. 
     
     
       10. The aqueous leather treatment composition according to  claim 1 , wherein said addition polymer particles have a glass transition temperature in the range of from −45° C. to 10° C. 
     
     
       11. The method according to  claim 5 , wherein said addition polymer particles have a glass transition temperature in the range of from −60° C. to 10° C. 
     
     
       12. The method according to  claim 5 , wherein said addition polymer particles have a glass transition temperature in the range of from −45° C. to 10° C.